So if you can't have perfect privacy, you'll have nothing at all? That's quite an all-or-nothing way of looking at this issue.
Well, I was out today when it started raining. I had my raincoat and my wellies in my rucksack, but I didn't have any water proof pants. I'd like to be dry, but unless I could get water proof pants, I'm not going to be dry, so ...
In cases where its realistic in the current world to get privacy, I'll take everything I can get: eg I still think there's a reasonable shot at eventually making cities enforce rules that prevent people from bringing a drone to my window on the 5th freagin floor to take pictures of my bedroom, and I'll certainly push for that to death.
I don't think that's the point; I think the OP is saying that in OP's particular case, the marginal benefit of Facebook privacy is much smaller than the marginal benefit of privacy in other aspects of life, and the lack of privacy from these various other aspects seem to be here to stay, therefore why worry about something relatively trivial like Facebook?
There may be other fallacies in OP's assumptions of course, but those notwithstanding I agree with the underlying logic. E.g. if I deem riding motorcycles an acceptable risk, then arguably I shouldn't spend energy worrying about whether my airplane will crash.
On the other hand, my identity has been stolen 16 billion times by now. Even if it didn't, I own real estate, which means you can infer a hell of a lot of info about me by just looking up my property tax bill, which is public. You could cross reference a lot of data source and get way more than I've ever put on Facebook. Ironically, if you wanted to make my life miserable, Facebook is probably not the first, second, or third place you'd want to go to get the juicy stuff.
So yeah, it's pretty hard to care after a while. My credit reports are frozen, I post on social medias as if I was doing so under my first and last name, assuming they're public anyway, there doesn't exist any embarrassing picture of me or my immediate family in any form (at least that I know of), etc.
I'd like to have privacy, but even if I take every measure I can take, unless I get rid of my credit cards, bank accounts, house, etc, I'll never have it anyway, so...